Niflheim - The Realm of Ice
Niflheim is the primordial realm of ice, mist, and cold from before creation.
Niflheim is eternal ice and mist, the opposite of Muspelheim's fire. From its eleven rivers came the ice that filled Ginnungagap. Niflheim represents the cold, dark aspects of existence - yet without it, creation could not have occurred.
First there was Niflheim, where eleven poisoned rivers flow from Hvergelmir.
Niflheim represents the necessary cold that balanced fire in creation.
Prose Edda